Passing of storm lets BP restart spill effort

Workers had been preparing to leave the area, and one of the rigs drilling a relief well had been detached. But tropical storm Bonnie diminished into a "disorganised area of showers and thunderstorms" before reaching the area, forecasters said.

The storm caused flooding in Haiti, Puerto Rico and the Dominican Republic, but there were no reports of significant damage as it passed over Florida.

It was downgraded to a tropical depression, and the US National Hurricane Centre said yesterday that it was "unlikely" the system would worsen, with a "near zero" chance of a tropical cyclone developing.

"Environmental conditions are not favourable for strengthening and the depression will probably continue with 25 knots until it moves inland," a spokesman said. "Because Bonnie is not expected to re-intensify… all coastal tropical storm warnings have been discontinued."

A BP spokeswoman said the Development Driller III, which is boring a relief well, had detached itself and moved away from the spill site.

She said it was now heading back, and all other vessels were preparing to resume operations.

BP hopes to use two relief wells to permanently seal the leak.

The oil firm placed a containment cap on the well last week and closed it off, stopping the flow for the first time since April, when an explosion on the Deepwater Horizon rig set the crude gushing and killed 11 workers.

The approach of the storm hampered efforts by BP to permanently plug its leaking oil well in the Gulf.

It also prompted oil and natural gas producers to evacuate many offshore workers, shutting down nearly 30 per cent of Gulf oil production and about 10 per cent of gas output.

Bonnie was the second named storm of the Atlantic hurricane season, which began on 1 June and runs until the end of November.

Forecasters expect this year's hurricane season to be particularly active.